Is CVE-2026-85390 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-85390?

CVE-2026-85390 has a CVSS v3 severity of HIGH (7.1).

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CVE-2026-85390

Description

Checkmate through 3.11.0 omits the isAllowed role guard middleware on maintenance-window, notification, and check-deletion routes, allowing read-only users to perform administrative actions. Attackers with user-role sessions can create arbitrary maintenance windows to silence alerts, modify notification channels, and delete monitor check history to erase incident evidence.